Hi,
In the situation below the note issued by the dispatch algo doesn't
seem right:
setClass("A", representation(stuff="complex"))
setAs("ANY", "A", function(from) new("A", stuff=as.complex(from)))
> as(6, "A")
An object of class "A"
Slot "stuff":
[1] 6+0i
> as(6L, "A")
Note: Method with signature ‘numeric#A’ chosen for function ‘coerce’,
target signature ‘integer#A’.
"ANY#A" would also be valid
An object of class "A"
Slot "stuff":
[1] 6+0i
First thing is that the note is in contradiction with the output of
selectMethod (seems like it's the method with signature "ANY#A" that
was chosen, not the method with signature "numeric#A"):
> selectMethod("coerce", c("integer", "A"))
Method Definition:
function (from, to = "A", strict = TRUE)
new("A", stuff = as.complex(from))
Signatures:
from to
target "integer" "A"
defined "ANY" "A"
Second, and more importantly, there is no need for a note in the first
place because there is no ambiguity at all (the method for "numeric#A"
itself is inherited from "ANY#A"):
> selectMethod("coerce", c("numeric", "A"))
Method Definition:
function (from, to = "A", strict = TRUE)
new("A", stuff = as.complex(from))
Signatures:
from to
target "numeric" "A"
defined "ANY" "A"
showMethod gives me an overview of the situation (which is much
simpler/cleaner than what the note is suggesting):
> showMethods("coerce")
Function: coerce (package methods)
from="ANY", to="A"
...
from="integer", to="A"
(inherited from: from="ANY", to="A")
...
from="numeric", to="A"
(inherited from: from="ANY", to="A")
Finally, if I switch the order (i.e. if I do 'as(6L, "A")' before
'as(6, "A")'), I don't get the note.
I get this with R 2.15.1 and a recent R devel (2012-09-22 r60777).
It looks like a regression because I was not able to reproduce with
R <= 2.14.
Thanks,
H.
--
Hervé Pagès
Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N, M1-B514
P.O. Box 19024
Seattle, WA 98109-1024
E-mail: hpa...@fhcrc.org
Phone: (206) 667-5791
Fax: (206) 667-1319
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